1. The Field of the Invention
The present invention relates to deduster apparatus and in particular represents an improvement over my previous inventions described in U.S. Pat. Nos. 4,299,693 and 4,631,124.
2. The Prior Art
It is well known that, in the field of transporting particulate product, commonly powders, granules, and the like generically referred to as powders, it is important to keep the product as free as possible of contaminants. Contaminants would include both foreign material as well as broken particles or streamers of the product being transported. In either case, using plastics as an example, such foreign material would have a detrimental effect on the finished product. Specifically, foreign material different in composition from the primary material, such as dust, and non uniform material of the primary product, such as streamers, would not necessarily have the same melting temperatures as the primary product and would cause flaws when the plastics material is melted and molded.
There have been many attempts to come up with means for transporting particulate product without causing breakage of the product and for separating out foreign matter of all types so that a substantially uniform clean product is delivered.
In my previous patents, mentioned above, I described apparatus which used neutralization of static charges together with counter flow of air currents to separate lighter dust particles from the main product being transported. Subsequently I have learned that there is more to separating dust, streamers, and the like than just passing the material through a magnetic field. Different materials require different handling because the charges which they carry may vary depending upon the makeup of the primary product. Thus it is desirable to not only pass the material through a magnetic field, but to vary that magnetic field to achieve a magnetic resonance which will effectively neutralize the charge of the dust and debris adhering to the primary particulate product.